My research focus is soil fertility based, investigating nutrient cycling in introduced and native grasslands, including soil-plant interactions. I have particular research interest and expertise in nitrogen (N) and phosphorus (P) cycling and soil pH (acidity) issues in soil/plant/animal systems. This research includes detailed investigations of soil chemistry, from rhizosphere to field and landscape scales. My aim is to improve the efficiency and effectiveness of our grassland farming systems, towards the future sustainability of grazed grasslands. An example of my work is, in collaboration with colleagues in China, examining nutrient flows and sustainability issues in high altitude Chinese and New Zealand grasslands.